Electric switch



April 20 1937- G. J. MEUER 2,077,576

ELECTRIC SWITCH F'iled Nov. 9, 1934 INSULHTION INSULHTION Patented Apr. 20, 1937 UNITED STATES PATT I 2,077,576 ELECTRIC swrrCn George J. Mener, Milwaukee, Wis., assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application November 9, 1934, Serial N 752,202

8 Claims.

A primary object of the invention is to provide novel means for relieving pulling strains upon the end-wiring terminals of switches of the aforementioned character.

Another and more specific object is to provide a Strain relief device in the form of an attachment for switches of known construction.

Another object is to generally improve the details of construction, assembly and operation of the parts of switches of the aforementioned l5 character.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawing illustrates certain embodiments of the invention which will now be described, itfbeing understood that the embodiments illustrated are susceptible of modification as to certain details of construction thereof without departing from the scope of the appended claims.

The snap switches herein disclosed are in general of the character described and claimed in my prior patents, No. 1,889,259, dated Nov. 29, 1933, and No. 1,977,078, dated Oct. 16, 1934, to which patents reference may be had for a more detailed deccription of certain elements of the switch mechanism.

In the drawing, Figure 1 is a vvertical sectional View of an electric snap switch of the end-wiring type, having my improved form of wiring terminal strain-relief applied thereto.

Fig. 2 is an end view of the switch illustrated in Fig. 1.

Fig. 3 is a bottom plan view of the switch shown in Figs. 1 and 2.

Fig. 4 is a perspective view of a modified for of strain-relief plate, which may be substituted for that shown in Figs. 1, 2, and 3.

Fig. 5 is a bottom plan view of a switchv like that shown in Figs. 1 and 2, but having a modied form of strain-relief plate of the character best illustrated in Figs. 6 and 7.

Fig. 6 is a fragmentary end view of a switch, with the strain-relief plate shown in section to illustrate the manner of inserting the straight bared ends of the circuit Wires.

Fig. 7 is a perspective view of the strain-relief plate shown in Figs. 5 and 6, and

Fig. 8 is a top plan view of a switch, with certain of the actuating elements removed, and

showing a type of wiring requiring a strain-relief plate of the character illustrated in Figs. 1l

yto 3 or Fig. 4.

Referring first to Figs. 1 to 3, the numeral i5 designates an insulating base which is preferably molded from a phenol formaldehyde con- 5 densation product. Said base is recessed from its upper surface to provide a chamber in which are located two pairs of resilient contacts I6, il and i8, I9, the tips of which contacts are biased toward each other, as best illustrated in Fig. 1. 10

Interposed between the respective pairs of contact tips at all times is a at punched plate 20 of insulation, said plate being slidable over the at upper surface 2i of a rib formed upon the bottom wall of said chamber. Plate 20 is notched at 15 opposite side edges thereof to receive a pair of U-shaped contactors 22 and 23, the arms of each contactor being exposed on opposite sides of said plate. In one eXtreme position of plate 20 the contactors carried thereby are moved into bridg- 20 ing engagement with the respective pairs of contact tips (Figs. 1 and 8), and in the other extreme position of said plate the contactors are disengaged from said contacts.

superimposed upon plate 2E is a relatively 25 smaller punched plate 2d of insulation, said plates 24 andl22 having registering openings of rectangular contour to receive with a close m the reduced lower end of a at punched sheet metal member 25, said reduced lower end being 3o upset over the lower surface of plate 22 to secure said parts to eachother. The switch actuating mechanism preferably comprises a wire member 26 of substantially W-form (as shown in detail in my Patent No. 1,977,078), said member being 35' 30, said bushing having alined openings formed 40` therein to receive a pivot pin 3|. Pin 3| is provided with a slightly enlarged intermediate portion (not shown) to provide for a drive fit thereof in an opening formed in the iiat punched sheet metal actuating lever 32, said lever being of the 45 desired length and having a ball or knob (not shown) attached thereto with a drive fit. The upper closed end of bushing 30 is provided with a kerf to permit oscillatory movement of lever 32.

A coiled compression spring 33 is engaged at 50 its lower end with member 26, the upper end of said spring being provided with a metal cup member to receive an abutment formed at the lower end of lever 32. A relatively thin punched insulating member 34 is interposed between the 55 member 26 and the stationary and movable contact elements of the switch to properly insulate the latter from the former, said member 34 having a slot (not shown) formed therein to 5 provide clearance for member 25. Also as will be apparent, the provision of insulating plate 24 insures a relatively large linear distance between the stationary and movable switch contacts and `the member 25,l thus .-increasing the current l0 making and breaking capacity of the switch.

Top plate 29 is secured to base I5 as by means of a pair of screws the Shanks of which are shown at 35 and 36, the heads of said screws being located in countersunk recesses in the bottom surface of said base, as shown in my patents aforementioned. The respective stationary contacts of the switch are attached to base I5 at the four corners of the latter and in a plane offset downwardly from the upper surface of said base, as by means of eyelets 31, 38, 39, and 40. Said eyelets also act to secure in position the horizontal portions 4I, 42, 43, and 44 of the endwiring terminal members of the switch, said members having depending vertical portions which are adapted to abut against shoulders formed on the respective ends of the base I5 to prevent inward bending of said vertical portions as an incident to tightening of the respective binding screws. Binding screws 45, 46, 41, and 48 are located adjacent to the lower ends of the vertical portions of the terminal members, and base I5 is provided with recesses to alord clearance for the Shanks of said screws. A at punched plate 49 of insulation is interposed between the upper surface of base I5 and top plate 29 to properly insulate the latter from the aforementioned wiring members.

In wiring a switch of the character herein described it is frequently necessary or desirable to employ relatively large gage solid wires of the character illustrated, whereas upon bending of said wires or upon pulling of the same (or any type of wire) endwise of base I5 an undesirable strain is placed upon the vertical portions of the wiring terminal members, with resultant liability of outward bending or distortion of the latter. To overcome this diiiculty in a simple and economical manner, I provide a flat punched insulating plate which is provided with a pair of rela- 50 tively large substantially circular openings adjacent to each end thereof, said openings being designated by the numerals 5I, 52, 53, and 54. 'I'he arrangement of said openings is preferably such that upon seating of plate 50 against the lower surface of base I5, the circularly looped ends of the wires may be inserted upwardly through the respective openings at a sucient outward angle to clear the lower end of base I5 and the lower extremities of the terminal members. The wire ends are then positioned vertically as shown in full lines in Figs. 1 and 2 toA bring the respective loops in alinement with the tapped openings in said terminal members. 'Ihe aforementioned binding screws are. then applied to mechanically and electrically connect the wire ends to the terminal members.

If the wire ends are bared to the proper length,

the shoulders formed by the ends of the respective wire sheaths will act to restrain plate 50 against vertical displacement. In ordinary usage, however, it is desirable to provide a. substantially right angled bend in each wire, as

shown in dotted lines in Fig. 1. In order to prevent endwise displacement of plate 50 relatively to base I 5 I prefer to provide the former with an opening 55 to accommodate a substantially rectangular projection I5m formed on the lower surface of said base. Thus upon bending of the several wires in the manner indicated in dotted lines in Fig. 1 the outer edges of the respective 5 openings 5I to54 will act as snubbing shoulders to prevent transmission to the terminal members of any bending or outward pulling strains upon the wires, the interlock between plate 50 and projection I58L assisting in the performance 10 of this function. Moreover, it will be apparent that outward bending of the several wires will serve to securely clamp plate 50 against the bottom surface of base I5.

The modified form of wiring terminal strain- 15 relief plate 5I)EL shown in Fig. 4 is provided with the aforedescribed openings 5I to 54, inclusive, and the same is additionally provided with a` pair of openings 56 and 51 which are adapted to receive the Shanks of a pair of securing screws 20 (not shown) which are relatively longer than the screws 35 and 36 aforementioned. The heads of said longer screws are adapted to engage the lower surface of plate 50 to provide for factory assembly thereof whereby the same is retained 25 in seated position against the lower surface of base I5 independently of the circuit wires.

In Figs. 5, 6, and '7 I have shown a wiring terminal strain-relief plate 58 which is provided with openings 55, 56, and 51 like those 30 shown in Fig. 4. However, plate 58 is provided with two pairs 59, 60, 6I, and 62 of relatively small circular openings, which pairs are offset inwardly from diagonally opposite corners of the plate. Said openings are just sufficiently large 35 to provide for upward insertion of the straight bared ends of the respective circuit wires 63, 64,

65, and 66, and said openings are so arranged as to insure positioning of the wire ends at the left-hand sides of the respective screw shanks 40 (Fig. 6). With this arrangement the binding screws need not be entirely removed from the terminal members to permit insertion of the wire ends, whereas upon tightening of the screws the wire ends are securely clamped by the screw 45 heads in mechanical and electrical contact with the respective terminal members.

The walls of the respective openings 59 to 62, inclusive, serve as snubbing shoulders upon bending of the several wires in the manner indicated 50 in dotted lines in Fig. 1, whereby the downwardly extending portions of the several terminal members are relieved of outward bending strains as an incident to an outward pull upon the circuit wires. As aforeindicated, the opening 55 in plate 55 58 is adapted to accommodate the projection I5a on the bottom surface of base I5. It is to be understood, of course, that the shorter length screws 35 and 36 of Figs. 1 and 2 may be substituned for the screws s1 and sa in Figs. 5 and 6, 60 to provide for support of plate 58 solely by the circuit wires upon bending of the latter, the walls of opening 55 cooperating with projection I5 in such case to prevent displacement of plate 56 longitudinally of base I5. 6J

What I claim as new and desire tov secure by Letters Patent is:

1. In an electric switch, in combination, a molded insulating base, a punched and stamped sheet metal terminal member having a flat por- 70 tion thereof secured to said vbase in a plane offset downwardly from and parallel to the upper surface of the latter, said member having another portion thereof extending downwardly at right angles to said first mentioned portion and 75 'adapted' totseat against one'ed'of said base, a

wiring Aterminal screw having threaded engagement with said downwardly extending portion,y

said base having a recess to accommodate the shank of said screw, a iiat punched plate of insulation underlying said base and lrestrained against movement relatively thereto, said plate having an'opening formed therein to provide for upward insertion of a bared wire end, whereby said wire end may be clamped by the head of said screw, and the wall of said opening providing a .snubbing shoulder for said wire to insure against outward displacement of said downwardly extending portion in the event of a pull upon said wire in a direction outwardly from said end of the base.

. 2. In an electric snap switch of the tool-handle type, in combination, a. molded insulating base having a plurality of wiring terminal members each having a portion thereof secured to said base in a plane oiiset downwardly from and parallel to the upper surface thereof and each also having a portion bent downwardly at substantially right angles to the first mentioned portion thereof to lie against an end wall of said base, a wiring terminal screw carried by each of said downwardly bent portions, a iiat punched plate of insulating material underlying said base and restrained against movement relatively to the latter in a given plane, said plate having a plurality of openings formed therein, said openings being respectively adapted to provide for upward Ainsertion of individual wire ends for clamping thereof by the heads of said screws, and the walls of said openings providing shoulders over which the wires may be bent to extend in a plane substantially parallel to said plate, said shoulders acting as snubbers to relieve any bending strains upon said terminal members as an incident to a pull upon any or all of said wires in the aforementioned plane thereof.

3. In an electric snap switch of the tool-handle type, in combination, a molded insulating base having a plurality of wiring terminal members secured'to and depending from the upper surface thereof at the respective ends of the base, wiring terminal screws having threaded engagement with said members at the lower ends thereof respectively, said base having a projection formed on the lower surface thereof, a at punched plate of insulating material underlying said base, said plate having an opening to accommodate said projection and the walls of said opening being adapted to cooperate` with said projection to prevent substantial displacement of said plate in the normal plane oi. the latter, said plate having a plurality of openings formed therein to provide for upward insertion of the bared ends of a corresponding number of circuit wires for clamping of the latter by the heads of the respective terminal screws, the walls of said openings respectively providing shoulders whereby said wires may be bent to extend from opposite ends of said base in a plane substantially parallel to the lower surface of the latter, and said shoulders acting to relieve strains upon said terminal members as an incident to a pull upon the respective wires in the Y plane aforementioned.

4. In an .electric snap switch of the tool-handle type, in combination, a molded insulating base having a plurality of wiring terminal members secured to and depending from the upper surfacethereof at the respective ends of the base, wiring terminal screws having threaded engagementwith said members at the lower ends there- .of respectively, said base having a projection formed on the lower surface thereof, a flat punched plate of insulating material underlying said base, said plate having an opening to accom- Y.

modate said projection and the walls of said opening being adapted to cooperate with said projection to prevent substantial displacement of said plate in the normal plane of the latter, said plate having a plurality of openings formed therein and adapted upon assembled positioning thereof with respect to said base to provide for upward insertion of the bared ends of a corresponding number of circuit wires for clamping of the latter by the heads of the respective terminal screws, the walls of said openings respectively providing shoulders whereby said individual wires may be bent to extend from opposite ends of said base in a piane substantially parallel to the lower surface of the latter, said shoulders acting to relieve strains upon said terminal members as an incident to a pull upon the respective wires in the plane aforementioned, and means independent of said wires for initially'retaining said plate in assembled relation to said base.

5. As an article of manufacture, a wiring terminal strain-relief attachment for electric snap switches of the end-wiring type, said attachment consisting of a flat punched plate of insulation adapted to underlie the insulating base of a switch, said plate having a plurality of pairs of openings formed therein adjacent to the opposite ends thereof to provide for upward insertion of the bared ends 'of circuit Wires in definite alinement with the wiring terminals,v and said openings respectively providing snubbing shoulders against which the individualwires may be bent to thereby substantially eliminate any outward pulling strains upon the respective wiring terminal members to which said wires are attached.

6. As an article of manufacture, a wiring terminal strain-relief attachment for electric snap switches of the end-wiring type, said attachment consisting of a fiat punched plate of insulation adapted to underlie the insulating base of the switch, said plate having a centrally located substantially rectangular opening formed therein to accommodate a correspondingly shaped projecv tion formed on the switch base, said plate having a pair of openings formed therein adjacent to each end thereof and offset inwardly from diagonally opposite corners of said plate, said pairs of openings being only suiciently large to provide for upward insertion of the straight bared ends of circuit wires employed with said switch;

the walls of said pairs of openings respectively providing snubbing shoulders to relieve any outward pulling strains upon the switch terminal members as an incident to pulling of the individual circuit wires in directions away from the opposite ends of the base, and said plate having an additional pair of openings formed therein,I said last mentioned openings providing clearance for the shanks of the securing screws of the switch the heads of which screws clampingly engage said plate to provide for retention thereof in assembled relation to the switch base.

7. As an article of manufacture, a wiring terminal strain-relief attachment for electric snap switches of the end-wiring type, said attachment consisting of a flat punched plate of insulation adapted to underlie the insulating base of a switch, said plate having a pair of penings `:formed therein and located inwardly a substantial distance from the respective ends thereof,

said openings being adapted for cooperation with the usual securing screws of the switch to provide for retention of saidplate in assembled re- 5 lation to the switch base, said plate also having a plurality of pairs of openings formed therein adjacent to the opposite ends thereof to respectively provide for upward insertion of the bared ends of individual circuit wires, the walls of said last 10 mentioned openings providing snubbing shoulders against which the respective wires are bent to thereby relieve any outward pulling strains upon the respective wiring terminal members to which said wires are attached. 1:, 8. As an article of manufacture, a wiring terminal strain-relief attachment for electric snap switches of the end-wiring type, said attachment consisting of a fiat punched plate of insulation adapted to underlie the insulating base of a 20 switch, said plate having a substantially centrally located opening formed therein to accommodate a correspondingly shaped projection on the switch base, said plate having a pair oi' openings formed therein respectively adjacent to opposite ends of said central opening, said last mentioned openings being adapted for cooperation with the usual securing screws of the switch, to provide for retention of said plate in assembled relation to the switch base, said plate also having a plurality of pairs of openings formed therein, each pair being located adjacent to one end of said plate to respectively provide for upward insertion of the bared ends of individual circuit wires, the walls of said last mentioned openings providing snubbing shoulders against which the respective wires are bent to thereby relieve any outward pulling strains upon the respective wiring terminal members to which said wires are attached.

GEORGE J. MEUER. 

